Are we being harmed because we receive too much, instead of too little, medical care?

For many Americans, the answer increasingly is yes.

In March, a new study showed a link between the iodine contrast that patients receive for routine medical scans and thyroid disease. Researchers found people with thyroid disease were two to three times as likely to have received this agent than those who did not develop it. Only two years prior, another study in the same journal, Archives of Internal Medicine, estimated radiation from medical scans was responsible for as many as 30,000 new cases of cancer and 15,000 deaths every year.

Such scans and medical procedures are necessary and even life-saving for many of the patients who receive them. For many others, however, they are not. These patients end up undergoing medical interventions that do not benefit them, yet still put them at risk for serious complications.

I have seen such complications as a physician. One of my patients suffered kidney failure and required lifelong dialysis because of medications he had unnecessarily received years ago. Others incurred heart damage or infections from procedures they did not need.

Unnecessary medical care is common in our country. It accounts for more than $200 billion in health care care spending every year according to the Institute of Medicine. Yet the uncertainties of modern medicine make it difficult for us to determine when an intervention is necessary and when it is not. That task is rightly left to the clinical judgment of individual physicians.

There are cases, however, where the medical literature renders a clear verdict. Certain interventions, such as antibiotics for viral respiratory infections, have been studied repeatedly and found to be of no benefit to patients. Other examples include cardiac stents for cases of mild chest pain and certain procedures for back pain.

Yet, despite the evidence against their effectiveness, such interventions persist. For example, there were more than 100,000 recorded cases of vertebroplasty — a back procedure that recently was shown to be of no benefit to patients — performed in one year. In another example, a recent study documented as many as 75,000 cases of patients receiving cardiac stents for inappropriate reasons. The complications from these two procedures, while rare, include blood clots, bleeding and even death.

These unnecessary medical interventions largely are a result of our distorted system of paying for medical care. Under the current "fee for service" model, insurers reimburse hospitals and doctors based on the volume of interventions they perform. It is easy to understand why this incentivizes more tests and procedures across the medical system without enough attention paid to whether patients end up benefiting.

Another culprit is a widespread assumption in medicine that "more is better." Both physicians and patients tend to overestimate the benefits of medical interventions, especially when advanced technologies are involved. This was documented in one recent study in which more than 80 percent of patients who were about to receive an invasive procedure did not understand its limitations even though they already had consulted their doctors.

Paradoxically, the lack of access and fragmentation that plagues our current system exacerbates this problem. Patients who cannot see a primary care doctor often end up in emergency rooms where physicians who do not know their medical history are compelled to order more tests.

Fortunately, there are some signs of change. The Affordable Care Act will help by increasing access to care, and encouraging more research into the effectiveness of certain interventions. It also will fund pilot projects to evaluate new ways of paying for health care instead of the traditional fee-for-service model.

Physician organizations are speaking out as well. The National Physicians Alliance, for example, has embarked on a Good Stewardship Project to draw attention to medical interventions that do not benefit patients.

We must also strive toward a health care system that truly values informed consent. Patients need the resources to make informed choices. This includes sufficient time with their physicians to have all their questions answered, as well as educational materials that clearly outline the risks and benefits of interventions. Research has shown patients, when properly informed, opt against medical interventions that are unnecessary.

My advice to patients and families is to be more critical when offered a medical intervention, whether a diagnostic test, a medication or a procedure.

Make sure to ask some basic questions upfront: What is its anticipated benefit? Its limitations? What are the most common complications? The most dangerous? Are there any feasible alternatives? What are the consequences of forgoing this intervention?

Don't be rushed into a decision. Ask where you can find additional information.

And remember more is not always better.

Basim Khan is a primary care physician in Alexandria and a member of the board of directors of the National Physicians Alliance.